Lightning arrester configuration



Oct. 13, 1970 R. E. KENNON LIGHTNING ARRESTER CONFIGURATION 2Sheets-Sheet 1 Filed April 16, 1969 INVENTOR Richard E BY 7 i ATTO NEYOct. 13, 1970 R. E. KENNON LIGHTNING ARRESTER CONFIGURATION 2Sheets-Sheet 2 Filed April 16, 1969 FIG.4.

v a a I fw I6 -IF A o JAM m1! -IMOLI \v 1.1.. Q c m "Q v c B B UnitedStates Patent Office 3,534,221 Patented Oct. 13, 1970 3,534,221LIGHTNEJG ARRESTER CONFIGURATION Richard E. Kennon, Bloomington, Ind.,assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., acorporation of Pennsylvania Filed Apr. 16, 1969, Ser. No. 816,485 Int.Cl. H01} 7/44 U.S. Cl. 31536 6 Claims ABSTRACT OF THE DISCLOSURE Voltagegrading and cascading arrangement for a lightning arrester employing atleast three equally spaced vertical columns of arrester componentsincluding spark gap devices, the arrangement including insulating traysstrategically located in each column between the components, and meansconnecting each tray in each column alternately across two adjacent,serially connected spark gap devices in two adjacent columns, the traysproviding voltage grading and cascading capacitances in each column, andthe connecting means electrically connecting the arrester components inelectrical series.

BACKGROUND OF THE INVENTION The present invention relates generally tolightning arresters, and particularly to an arrester configuration inwhich insulating trays provide strategically located capacitances incolumns of arrester components.

In application Ser. No. 679,315 (W. E. 39,078) filed Oct. 31, 1967 byJohn E. Harder and assigned to the present assignee, there is discloseda voltage grading and cascading circuit arrangement which permits theuse of a single accurately controlled or critical spark gap to initiatethe sparkover of a complete arrester. The circuit comprises at least twogroups of serially connected capacitors with each capacitor in eachgroup alternately connected across two adjacent, serially connected mainspark gap devices. Voltage cascading occurs when the controlling gapsparks over, the voltage across this gap being instantly transferred tothe adjacent main gap in parallel with one of the grading capacitors.This results in an instant increase in the voltage across the adjacentgap thereby enhancing its ability to spark over. When it does spark overthe parallel capacitor discharges thereby instantly transferring itsvoltage to the remaining unfired gaps and associated capacitors which,in turn, increases the firing capabilities of the unfiredgaps. Thisoperation continues, and occurs rapidly, until all gaps are fired.

BRIEF SUMMARY OF THE INVENTION The present invention is a mechanicalconfiguration and structure using the above, briefly described voltagecascading circuit of the Harder application in a manner in which theprinciple capacitances form a structural part of the configuration. Moreparticularly, the invention includes at least three columns ofvalve-type resistance blocks and spark gap devices, the resistanceblocks and gap devices being supported and separated by insulating trayswith metal connectors seated in the insulating trays. The metalconnectors are interconnected among the columns and between the trays ina manner to connect the blocks and gap devices in electrical series andto alternately connect the trays across two electrically adjacent sparkgap devices. The trays, with their inherent capacitances, thus appear inthe circuit at the precise locations required to effect the voltagegrading and cascading function while simultaneously forming a part ofthe arrester structure. Further, by locating the inherent capacitance ofthe trays in the manner briefly described thus far, the inherentcapacitance is prevented from the appearing elsewhere in the arrestercolumns and circuit in an unwanted fashion which could upset voltagebalance and prevent the very desirable cascading eflect.

THE DRAWINGS The invention, including its objectives and advantages,will become more apparent from reading the following detaileddescription in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of connecting structures forinterconnecting grading capacitances with arrester components inaccordance with the principles of the present invention;

FIG. 2 is a top plan view of the structure shown in FIG. 1;

FIG. 3 is a schematic representation showing the paths for current flowin the structure of FIG. 1; and

FIG. 4 is a side elevation view (in partial section) of a capacitancetray employed in structure of FIGS. 1 and 2.

PREFERRED EMBODIMENT Specifically, FIG. 1 shows structure 10 forconnecting arrester component groups 11 (FIG. 3) disposed in threeequally spaced apart column structures in electrical series, and forsimultaneously interconnecting voltage grading capacitances trays 13(FIG. 4), forming a part of the column structures, between said columnsin a manner to alternately connect each tray across two electricallyadjacent component groups (including spark gap devices) as disclosed inthe above mentioned Harder application.

For purposes of clarity of illustration, the arrester components 11 andthe trays 13 are not shown in FIGS. 1 and 2, and are onlyrepresentatively shown in FIG. 3. The components, however, would bestacked in three separate and equally spaced apart columns alongvertical axes designated A, B and C, in the figures, the use of separatecolumns per se being a well known expedient in the artester art toobtain high voltage ratings for arrester units without havingexcessively tall columnar structures that are difiicult and costly tosupport. In plan view, the columns form an equilateral triangularconfiguration as seen in FIG. 2.

Means for interconnecting vertical columns of components with gradingcapacitors are known in the arrester art. The difliculty arises,however, and the present disclosure solves the difiiculty, in combiningthe teachings and advantages of the above mentioned Harder disclosurewith those of the three column arrester unit. More particularly, what isneeded is a compact inexpensive structure which will connect thearrester component devices in the three columns in electrical series toobtain the desired high voltage rating, and, to connect each gradingcapacitance alternately across each two electrical adjacent componentdevices to obtain the voltage cascading efiect described in the Harderapplication and briefly described above. The structures shown in FIGS. 1to 4 meet these needs.

Thus, in FIG. 1, the structure 10 comprises a plurality of electricallyconductive connectors, generally designated 12 and 14, each connectorcomprising a plate portion 16 (shown in the form of a shallow pan)having an integral strap portion 18 extending outwardly therefrom and atan obtuse angle with the plane of the plate portion. The connectors 12and 14 are identical to each other except for the ends of the integralstrap portions 18. The strap end of the connector 12 has a fiat,rectangular configuration while the strap end of the connector 14 isprovided with inwardly folded wing portions 20 adapted to receive andcrimp the flat end of the connector 12 as shown in FIG. 1. In thismanner, the plate portions 16 of each connector are electricallyinterconnected.

The connectors 12 and '14 are shown further provided with a secondintegral strap or arm portion 22 extending outwardly from the plate 16in a plane substantially parallel therewith. The angular relationship ofthe strap 18 and the -arm 22 in the plane of the plate is acute for theplate 14 and obtuse for the plate 12 such that when the straps 18 aredisposed towards each other for mutual connection, the arms 22 extendoutwardly from the triangular confi-guration of connectors when soconnected as shown in FIG. Q. The purpose of the arms is to securegrading resistors and auxiliary capacitor components in a mannerpresently to be explained.

Between the plate portions 16 of the connectors 12 and 14 are disposedthe insulating annular trays 13 (FIG. 4) in the manner shown somewhatschematically in FIG. 3. The trays are made from an insulating materialhaving a dielectric constant, which, when disposed between two adjacentplates 16 in the manner shown in FIGS. 3 and 4 form voltage gradingcapacitances strategically located in the three columns in the mannerexplained hereinafter.

Each tray 13 has two opposite sides or faces in which are providedcenter recesses adapted to receive and seat the connectors 12 and 14 asshown in FIG. 4, the plate portions 16 of the connectors formingelectrodes and terminals for the capacitances 25.

Each recess in each tray 13 is further adapted to receive and seat theend of a stack or group of the arrester components 11 as shown in FIG.4, the ends of each component group being disposed in electrical contactwith the plate portions 16 of he connectors 12 and 14. Each componentgroup includ es well known non-linear resistance blocks (not shown) andmain spark gap devices 27 only representatively shown in FIG. 3.

When the trays 13 and the components groups or devices 11 are properlylocated between the plate portions 16 of the connectors 12 and 14, thetrays and component devices form the three vertical columns along axesA, B and C.

Across each capacitance 25 may be connected an auxiliary capacitor 28suitably supported and electrically connected between the two integralarms 22 of the connectors 12 and 14. In this manner, the capacitor 28 isconnected in parallel with the tray 13 to provide additional gradingcapacitance if needed. In a similar manner, grading resistors 29 can beprovided, each resistor being connected between the arms 22 located atthe ends of each component device 11 as shown diagrammatically in FIG.3. When the auxiliary capacitors 28 and the resistors 29 are properlysecured between the ends of the arms 22, the capacitors and resistorsform three vertical columns along axes A, B 'and C in substantialparallel alignment with the axes A, B and C.

The three columns of arrester components and three of resistors 29 andcapacitors 28, as thus far described, are supported and commonlyconnected between top and bottom terminal plates (not shown) to form anarrester unit and circuit for electrical connection between a line andground to provide overvoltage and surge current protection for the lineand for electrical apparatus connected thereto. When the unit is calledupon to discharge a surge of current to ground, current flows seriallythrough the arrester component devices 11 by virtue of the structure 10,i.e., the connectors 12 and 14. In FIG. 3, a portion of such a unit isshown in schematic form, the path of current flow therethrough beingindicated by appropriate arrows.

Thus, in operation when the columns of the arrester components dischargea current surge to ground, current flows through each of the arrestercomponent devices 11, the flow starting with the first such device inthe circuit, i.e., the one device (not shown) connected directly to theabove mentioned top terminal plate. For purposes of explanation, thisone device may be the uppermost one (labelled 11C) on the center axis Cin FIG. 3. As indicated by the downwardly pointing arrow in the device110, current flows therethrough to associated plate 16 of the traycapacitor 25 located at the bottom of said device. The current is thenconducted upwardly and to the left along integral strap 18 and crimp 20to the plate 16 in the column of axis B, the plate being in electricaland physical contact with the top end of another component devicelabelled 11B.

Again, the current is conducted downwardly through the device 11B (incolumn B) until the current reaches the plate engaging the lower end ofsaid device. Again, an associated integral strap 18 conducts the currentupwardly (and this time to the right) to a capacitor plate 16 in columnA, and current is conducted downwardly through another component device(labelled 11A) in said column in electrical contact with said plate.From said plate, current is again directed upwardly and to the left viaintegral straps 18 to a plate 16 and the next component device 11 incolumn C in line and immediately below 11C.

The current conducting process described above continues down thecolumns in the manner described until it enters ground through anassociated ground terminal (not shown). As can be seen, the structure 10serially connects all of the arrester component devices 11 in the threecolumns A, B and C to provide the desired high voltage rating withoutnecessitating the use of tall columns of arrester components.

The structure 10, however, serves another highly important function,namely, that of connecting the capacitances 25 alternately across twoelectrically adjacent arrester component devices 11 to provide thehighly desirable voltage grading and cascading effect of the abovementioned Harder application. By referring again to FIG. 3, it is seenthat each insulating tray 13 with two associated plates 16 areelectrically connected across two of the serially adjacent componentdevices 11 by the integral straps 18 secured together by the crimpingfolds 20. For example, the middle tray 13 in column B is connectedacross the upper component device 11A in column A and the middlecomponent device 11 in column C by a set of integral interconnectingstraps 18, the two devices being electrically serially connectedtogether by another set of integral straps extending between the top ofdevice 11 in column C and the bottom of the device 11A in column A.

Thus, the structure 10 not only performs the two highly importantfunctions described above, but performs them in a compact and economicalmanner; The connectors 12 and 14 require a minimum of space in andbetween the columns, the connectors are identical to each other (exceptfor the end portions of 12 and 14 and the angle differences between 18and 22) thereby requiring a minimum of different parts, and theconnectors are relatively simple structures requiring minimum effort andcost to manufacture.

In addition to the above advantages, the configuration of the connectingstructure 10, with its deliberate locating of the inherent capacitanceof the trays 11 in the columns of arrester components, prevents theinherent capacitance of the trays 13 from appearing elsewhere in thecolumns in an unwanted fashion, i.e., in a manner that could upsetvoltage balance in the columns so as to prevent the voltage cascadingelfect.

It should now be apparent from the foregoing description that a new andhighly useful arrester configuration has been disclosed which providesseries connection for columns of arrester components whilesimultaneously locating and connecting component supporting insulatingtrays in a manner to provide voltage grading and cascading for theconfiguration.

Though the invention has been described with a certain degree ofparticularity, changes may be made therein without departing from thespirit and scope thereof.

What is claimed is:

1. A lightning arrester comprising a plurality of arrester componentdevices electrically connected in series and physically disposed in atleast three vertical columns, said component devices including spark gapdevices and nonlinear resistance blocks, individual insulating traysinterposed in each of said columns at spaced locations, conductive platemeans disposed on each side of each tray in contact therewith and inelectrical contact with the adjacent arrester component, and means forelectrically connecting each of the plate means to a plate means in adifferent column in a manner to connect all the arrester componentdevices in series.

2. A lightning arrester as defined in claim 1 in which said connectingmeans are strap members integral with the plates and extending from eachplate in position to engage a strap member of a plate in another column.

3. A lightning arrester as defined in claim 2 in which the trays andplates are generally circular and the plates are substantiallycoextensive With the arrester components.

4. A lightning arrester comprising a plurality of arrester componentdevices electrically connected in series and physically disposed in atleast three vertical columns, said component devices including spark gapdevices and nonlinear resistance blocks, individual insulating traysinterposed in each of said columns in spaced locations, conductive platemeans disposed on each side of each tray in contact therewith and inelectrical contact with the adjacent arrester component, voltage gradingimpedance elements including capacitors and resistors disposed adjacentsaid columns of arrester components, means for electrically connectingeach of the plate means to a plate means in a difierent column in amanner to connect all the arrester component devices in series, andmeans for connecting the plate means to said impedance elements toconnect the impedance elements across the arrester components.

5. A lightning arrester as defined in claim 4 in which each plate meanshas a first integral connector strap extending therefrom in position toengage a connector strap of a plate means in another column and a secondintegral connector strap extending therefrom in position to engage animpedance element.

6. A lightning arrester as defined in claim 5 in which said firstconnector strap of each platee extends therefrom at an obtuse angle tothe plane of the plate to extend toward another column, and said secondconnector strap extends in a plane substantially parallel to the planeof the plate, said impedance elements being received between the secondconnector straps of successive plates in the same column.

References Cited UNITED STATES PATENTS 2,611,108 9/1952 Rydbeck 3l5362,862,153 11/1958 Nilsson 317-99 3,069,589 12/1962 Cunningham 315-363,144,583 8/1964 Sorrow et al. 31536 3,366,831 1/1968 Lapple 315363,412,273 11/1968 Kennon et a1. 313-1 JOHN HUCKERT, Primary Examiner R.F. POLISSACK, Assistant Examiner US. Cl. X.R. 3l3325; 3 l535

